EPA & Volkswagen 20

[GregLocock]

PJGD- the VW cars fail consistently and spectacularly, not just spikes.

Figure 4.31 in the UWV report shows cumulative distribution of NOx emissions for vehicle B (Passat with SCR), split by test route. The 50th percentile emissions for each route varies from about 3 to about 20 times the EPA limit, there's only one test route (out of 5) where the NOx emissions even briefly meets the standard.

As such, yes, the values of 25 and 40 are rare, but virtually all the time the car is running at a substantial multiple of the EPA limits.

In comparison the X5 runs within 3 times of limit all the time, except for one type of test, and for several of the test routes stays well below EPA limit for 75-90% of the time.










Cheers

Greg Locock


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[JohnRBaker]

I was speaking for the entire state.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Digital Factory
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[IRstuff]

it's misleading in that at least the DWP is getting a sizable portion of its power from outside of the state, and DWP boasts of getting power from:

"The Intermountain Power Plant, near Delta, Utah, one of the largest coal-fired power plants in the nation, and the largest single source of electricity for DWP, at the moment. CLUI photo"

Very likely, other California utilities are doing something similar in getting power from plants that would not be necessarily operable in the state.

TTFN
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[tbuelna]

I got a chuckle from that 2013 LADWP brochure. As IRstuff noted, the 42% coal figure in the LADWP brochure is "purchased power" from out of state. There is only one small (50MW) electrical power plant using coal still operating in California, and it only supplies electricity to SCE (and not LADWP) during brief periods of high demand. What was even funnier in the LADWP brochure was that 98% of their "green power" supply came from burning biomass and waste.

 

[JohnRBaker]

You want to hear something funnier yet? Jeb Bush just released a 'policy paper' on how he would address the nation's energy needs if he were elected president, and the word 'renewable' does NOT appear once in the entire document.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Digital Factory
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[tbuelna]

JRB, don't believe everything you hear from NPR. Here's part of the energy policy text posted on Jeb's official website: "In addition, we must create a level playing field for all energy sources including, but not limited to, nuclear, renewables, coal, natural gas, oil and alternative fuels. We unnecessarily drive up energy costs on Americans when we play favorites and suppress the dynamism of free markets."

Nothing funny there. He is wisely considering domestic energy policy as part of the much larger economic situation. He wants free market economics to determine the mix of energy sources our nation uses. That would even include advanced diesel auto engines.

BTW, I don't plan on voting for Jeb Bush.

 

[PJGD]

Meanwhile, back on topic, there is this bit of incriminating evidence: Have a read of this large helping of hubris from the 2008 Vienna Symposium in which several people crow about how wonderful the 2.0L TDI engine is and how impressive the exhaust aftertreatment system is in meeting the Tier-2 Bin-5/LEV-2 regulations so that it is truly a Clean Diesel. One assumes that these authoring engineers are prime candidates for interrogation over this uber debacle.

In particular, read the section on the aftertreatment development and the final summary/wrap-up:

"The traditional strengths of the TDI, such as driving pleasure and economy are very
much to the fore in the cleanest diesel engine in the world.
We are therefore very certain that this new engine design will be a successful chapter
in the history of diesel vehicles in the American market.
With the "Clean Diesel" engine, VOLKSWAGEN has created a new milestone in
diesel technology on the American market".

You can say that again!

PJGD

 

[BrianPetersen]

It was pointed out on another forum that there is a legit reason for the existence of "dyno mode" - the underlying logic that determines if the vehicle is being operated on the road, or on a chassis dyno: ABS/ESP/TC systems (which the affected cars all have). Operating a two-wheel-drive car on a dyno would cause unwanted ABS/ESP/TC intervention. If the car can detect that it is operating on a dyno then the traction-control "nanny" can be switched off automatically and allow the powertrain to operate without intervention.

Of course, using that to enable emission controls in dyno mode but disable them otherwise, would be a problem.

 

[tbuelna]

PJGD- Thanks for the link to that paper, it was worth reading.

The 2008 paper describes a MY2009 2L passenger vehicle diesel engine capable of meeting US EPA Tier 2/Bin 5 emissions which uses an LNT device for treatment of NOx in the exhaust gas. The full emissions control system used on the engine is quite complex. The paper describes just how difficult it is to coordinate operation of all the emissions equipment over all the varying driving conditions required. The paper notes that at least 10 different modes of operation are required just for the emissions equipment (DPF, LNT, etc.). When you include the very high pressure/frequency digital CRI system, what VW achieved with that particular engine was indeed very impressive.

Consider that the EPA tier 2/bin 10 NOx limits for diesel passenger vehicles existing prior to 2008 were ~12X higher than tier 2/bin 5 NOx limits. Also remember that the VW vehicle models in question demonstrated during certification testing that they were capable of meeting emissions requirements. The NOV issued by the EPA claims VW violated US law by importing and selling vehicles that were not covered by a valid COC (Certificate of Conformity). The EPA claims the COCs issued to VW for the vehicle models in question were invalid due to the fact VW did not provide a full disclosure of the information required for the COC. The US DOJ will pursue a case against VW based on importing and selling vehicles without a valid COC, and also for not providing full disclosure in the COC applications.

 

[VEBill]

"Consider that the EPA tier 2/bin 10 NOx limits for diesel passenger vehicles existing prior to 2008 were ~12X higher than tier 2/bin 5 NOx limits."

So the "10x to 40x NOx" is roughly similar to the previous generation of emission standards.

 

[SomptingGuy]

That's my take on it too (10x - 40x is a bit like previous (or two back) generation requirements).

However...

Euro 3 (in EU, before 2005) could be achieved without aftertreatment. So I'm assuming that those untreated engines were compromising power, economy, driveability to squeeze through those limits. But once new limits are tight enough to force you to need NOx treatment, you might as well turn the engine back up. I wouldn't be surprised if contemporary VW diesels have higher engine-out NOx than the euro 3 compliant ones.

Steve

 

[Lou Scannon]

Quite so. Analagous to the situation with natural gas engines; in switching from lean-burn to stoich + cooled EGR, in order to take advantage of 3-way catalysis, engine-out NOx and CO skyrocket, but the catalyst efficiency takes care of that.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[dgallup]

Finally some of the details behind the cheating are coming to light

http://www.wsj.com/articles/vw-emissions-probe-zeroes-in-on-two-engineers-1444011602

And how much power the engines loses with the emission controls working

http://www.businessinsider.com/vw-diesel-engines-power-lose-without-cheating-software-2015-10

----------------------------------------

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[VEBill]

VW announces their solution:

 

[GregLocock]

Gosh, the car produced/ at the wheels/ more than the manufacturers claimed output at the flywheel? So you'd typically add 15% for driveline losses.

Also, does merely running in 2wd tell the ECU to flip into emissions mode? How would that work on a 2wd?

I call case very unproven.

Cheers

Greg Locock


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[140Airpower]

The ECU is car-specific. Knowing what to look for to detect emissions testing would be car-specific.

 

[Lou Scannon]

I agree with Greg, not enough detail about the test procedure, design of experiments (statistical validity), and measurement systems analysis. Regarding the reported power and torque, I assume correction factors were applied to go from chassis to flywheel results. Not to say that the correction factors are necessarily accurate.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[gruntguru]

Not convinced. The original story mentioned steering inputs and driving characteristics of the EPA cycle as triggers for the defeat SW.

If the video conclusions are to be believed, a reduction in output at low rpm (fuel reduction and/or retard and/or boost reduction?) is sufficient to eliminate a 30x over-emission of NOx.

Can anyone confirm that low-rpm, full-load is the region of greatest concern regarding NOx emissions?

je suis charlie

 

[Lou Scannon]

That's when peak combustion temperatures would be highest, due to lack of air for dilution.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[IRstuff]

"I call case very unproven."

?? VW, and every executive has admitted to VW doing it.

TTFN
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